clk: iproc: add initial common clock support

This adds basic and generic support for various iProc PLLs and clocks
including the ARMPLL, GENPLL, LCPLL, MIPIPLL, and ASIU clocks.

SoCs under the iProc architecture can define their specific register
offsets and clock parameters for their PLL and clock controllers. These
parameters can be passed as arugments into the generic iProc PLL and
clock setup functions

Derived from code originally provided by Jonathan Richardson
<jonathar@broadcom.com>

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>

1 files changed, 276 insertions, 0 deletions

diff --git a/drivers/clk/bcm/clk-iproc-asiu.c b/drivers/clk/bcm/clk-iproc-asiu.c
new file mode 100644
index 000000000000..e19c09cd9645
--- /dev/null
+++ b/drivers/clk/bcm/clk-iproc-asiu.c
@@ -0,0 +1,276 @@
+/*
+ * Copyright (C) 2014 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/clkdev.h>
+#include <linux/of_address.h>
+#include <linux/delay.h>
+
+#include "clk-iproc.h"
+
+struct iproc_asiu;
+
+struct iproc_asiu_clk {
+	struct clk_hw hw;
+	const char *name;
+	struct iproc_asiu *asiu;
+	unsigned long rate;
+	struct iproc_asiu_div div;
+	struct iproc_asiu_gate gate;
+};
+
+struct iproc_asiu {
+	void __iomem *div_base;
+	void __iomem *gate_base;
+
+	struct clk_onecell_data clk_data;
+	struct iproc_asiu_clk *clks;
+};
+
+#define to_asiu_clk(hw) container_of(hw, struct iproc_asiu_clk, hw)
+
+static int iproc_asiu_clk_enable(struct clk_hw *hw)
+{
+	struct iproc_asiu_clk *clk = to_asiu_clk(hw);
+	struct iproc_asiu *asiu = clk->asiu;
+	u32 val;
+
+	/* some clocks at the ASIU level are always enabled */
+	if (clk->gate.offset == IPROC_CLK_INVALID_OFFSET)
+		return 0;
+
+	val = readl(asiu->gate_base + clk->gate.offset);
+	val |= (1 << clk->gate.en_shift);
+	writel(val, asiu->gate_base + clk->gate.offset);
+
+	return 0;
+}
+
+static void iproc_asiu_clk_disable(struct clk_hw *hw)
+{
+	struct iproc_asiu_clk *clk = to_asiu_clk(hw);
+	struct iproc_asiu *asiu = clk->asiu;
+	u32 val;
+
+	/* some clocks at the ASIU level are always enabled */
+	if (clk->gate.offset == IPROC_CLK_INVALID_OFFSET)
+		return;
+
+	val = readl(asiu->gate_base + clk->gate.offset);
+	val &= ~(1 << clk->gate.en_shift);
+	writel(val, asiu->gate_base + clk->gate.offset);
+}
+
+static unsigned long iproc_asiu_clk_recalc_rate(struct clk_hw *hw,
+						unsigned long parent_rate)
+{
+	struct iproc_asiu_clk *clk = to_asiu_clk(hw);
+	struct iproc_asiu *asiu = clk->asiu;
+	u32 val;
+	unsigned int div_h, div_l;
+
+	if (parent_rate == 0) {
+		clk->rate = 0;
+		return 0;
+	}
+
+	/* if clock divisor is not enabled, simply return parent rate */
+	val = readl(asiu->div_base + clk->div.offset);
+	if ((val & (1 << clk->div.en_shift)) == 0) {
+		clk->rate = parent_rate;
+		return parent_rate;
+	}
+
+	/* clock rate = parent rate / (high_div + 1) + (low_div + 1) */
+	div_h = (val >> clk->div.high_shift) & bit_mask(clk->div.high_width);
+	div_h++;
+	div_l = (val >> clk->div.low_shift) & bit_mask(clk->div.low_width);
+	div_l++;
+
+	clk->rate = parent_rate / (div_h + div_l);
+	pr_debug("%s: rate: %lu. parent rate: %lu div_h: %u div_l: %u\n",
+		 __func__, clk->rate, parent_rate, div_h, div_l);
+
+	return clk->rate;
+}
+
+static long iproc_asiu_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+				      unsigned long *parent_rate)
+{
+	unsigned int div;
+
+	if (rate == 0 || *parent_rate == 0)
+		return -EINVAL;
+
+	if (rate == *parent_rate)
+		return *parent_rate;
+
+	div = DIV_ROUND_UP(*parent_rate, rate);
+	if (div < 2)
+		return *parent_rate;
+
+	return *parent_rate / div;
+}
+
+static int iproc_asiu_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+				   unsigned long parent_rate)
+{
+	struct iproc_asiu_clk *clk = to_asiu_clk(hw);
+	struct iproc_asiu *asiu = clk->asiu;
+	unsigned int div, div_h, div_l;
+	u32 val;
+
+	if (rate == 0 || parent_rate == 0)
+		return -EINVAL;
+
+	/* simply disable the divisor if one wants the same rate as parent */
+	if (rate == parent_rate) {
+		val = readl(asiu->div_base + clk->div.offset);
+		val &= ~(1 << clk->div.en_shift);
+		writel(val, asiu->div_base + clk->div.offset);
+		return 0;
+	}
+
+	div = DIV_ROUND_UP(parent_rate, rate);
+	if (div < 2)
+		return -EINVAL;
+
+	div_h = div_l = div >> 1;
+	div_h--;
+	div_l--;
+
+	val = readl(asiu->div_base + clk->div.offset);
+	val |= 1 << clk->div.en_shift;
+	if (div_h) {
+		val &= ~(bit_mask(clk->div.high_width)
+			 << clk->div.high_shift);
+		val |= div_h << clk->div.high_shift;
+	} else {
+		val &= ~(bit_mask(clk->div.high_width)
+			 << clk->div.high_shift);
+	}
+	if (div_l) {
+		val &= ~(bit_mask(clk->div.low_width) << clk->div.low_shift);
+		val |= div_l << clk->div.low_shift;
+	} else {
+		val &= ~(bit_mask(clk->div.low_width) << clk->div.low_shift);
+	}
+	writel(val, asiu->div_base + clk->div.offset);
+
+	return 0;
+}
+
+static const struct clk_ops iproc_asiu_ops = {
+	.enable = iproc_asiu_clk_enable,
+	.disable = iproc_asiu_clk_disable,
+	.recalc_rate = iproc_asiu_clk_recalc_rate,
+	.round_rate = iproc_asiu_clk_round_rate,
+	.set_rate = iproc_asiu_clk_set_rate,
+};
+
+void __init iproc_asiu_setup(struct device_node *node,
+			     const struct iproc_asiu_div *div,
+			     const struct iproc_asiu_gate *gate,
+			     unsigned int num_clks)
+{
+	int i, ret;
+	struct iproc_asiu *asiu;
+
+	if (WARN_ON(!gate || !div))
+		return;
+
+	asiu = kzalloc(sizeof(*asiu), GFP_KERNEL);
+	if (WARN_ON(!asiu))
+		return;
+
+	asiu->clk_data.clk_num = num_clks;
+	asiu->clk_data.clks = kcalloc(num_clks, sizeof(*asiu->clk_data.clks),
+				      GFP_KERNEL);
+	if (WARN_ON(!asiu->clk_data.clks))
+		goto err_clks;
+
+	asiu->clks = kcalloc(num_clks, sizeof(*asiu->clks), GFP_KERNEL);
+	if (WARN_ON(!asiu->clks))
+		goto err_asiu_clks;
+
+	asiu->div_base = of_iomap(node, 0);
+	if (WARN_ON(!asiu->div_base))
+		goto err_iomap_div;
+
+	asiu->gate_base = of_iomap(node, 1);
+	if (WARN_ON(!asiu->gate_base))
+		goto err_iomap_gate;
+
+	for (i = 0; i < num_clks; i++) {
+		struct clk_init_data init;
+		struct clk *clk;
+		const char *parent_name;
+		struct iproc_asiu_clk *asiu_clk;
+		const char *clk_name;
+
+		clk_name = kzalloc(IPROC_CLK_NAME_LEN, GFP_KERNEL);
+		if (WARN_ON(!clk_name))
+			goto err_clk_register;
+
+		ret = of_property_read_string_index(node, "clock-output-names",
+						    i, &clk_name);
+		if (WARN_ON(ret))
+			goto err_clk_register;
+
+		asiu_clk = &asiu->clks[i];
+		asiu_clk->name = clk_name;
+		asiu_clk->asiu = asiu;
+		asiu_clk->div = div[i];
+		asiu_clk->gate = gate[i];
+		init.name = clk_name;
+		init.ops = &iproc_asiu_ops;
+		init.flags = 0;
+		parent_name = of_clk_get_parent_name(node, 0);
+		init.parent_names = (parent_name ? &parent_name : NULL);
+		init.num_parents = (parent_name ? 1 : 0);
+		asiu_clk->hw.init = &init;
+
+		clk = clk_register(NULL, &asiu_clk->hw);
+		if (WARN_ON(IS_ERR(clk)))
+			goto err_clk_register;
+		asiu->clk_data.clks[i] = clk;
+	}
+
+	ret = of_clk_add_provider(node, of_clk_src_onecell_get,
+				  &asiu->clk_data);
+	if (WARN_ON(ret))
+		goto err_clk_register;
+
+	return;
+
+err_clk_register:
+	for (i = 0; i < num_clks; i++)
+		kfree(asiu->clks[i].name);
+	iounmap(asiu->gate_base);
+
+err_iomap_gate:
+	iounmap(asiu->div_base);
+
+err_iomap_div:
+	kfree(asiu->clks);
+
+err_asiu_clks:
+	kfree(asiu->clk_data.clks);
+
+err_clks:
+	kfree(asiu);
+}